Frequencies for first 10,000 rows of cardiac variable in natl1998 dataset :

    Cardiac |
    disease |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         55        0.55        0.55
          2 |      9,945       99.45      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015